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Do you have some sort of IDE or development environment connected against this server?

Because I can't tell you why you are getting these queries.

But I can tell you what they are.
The INFORMATION_SCHEMA.ROUTINES table is used to get information about and the definition of the stored procedures that you have created in your DB.

The SHOW VARIABLES are also used to get information about the current configuration of your DBMS.

And the only reason I can thing of why you get these is because you are running some sort of development tool against this DB.

As for the fact that you get a table scan for the query against INFORMATION_SCHEMA.ROUTINES it is nothing to worry about since that is actually not a table it is just a way to get meta information out from the DBMS.

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I believe I have found the problem. I was using the .NET connector (version 5.1.2.2). I have upgraded our systems to 5.1.4.0 and the number of queries have almost stopped. There maybe a rarely used system I've forgotten about that is still using the old connector.

A quick look through the CHANGELOG suggests that Bug 29098 MAY be the problem, but I haven't dug into it to confirm.

I will post back if I have further problems with this.

The reason it has been bothering me is that MONyog has been reporting 50% Full table scans, which is primarily these.